It's not something magical about the soil that makes people want to move to the US. It's the culture. The more people that can use it, the better, but add too many new people too fast and it suddenly stops working.
No dude, it's the money.
I have at least a dozen friends who are on H1Bs working in SV for different large software companies. They're either going there because that's where the best-paying jobs are or they're staying for just a couple of years to save some money.
If you were to beam all the Americans into space and them beam all the Mexicans into their place, they wouldn't magically achieve US levels of income just because of their physical location.
It's true that just swapping people places right now would not substitute anything. But you can bet that the immense natural resources, available land and influx of immigrants through the 20th century have impacts as much, if not more, important than whatever contemporary cultural trends exist.
Culture has a lot to do with it. Brazil had the immigrants (and still does have LatAm immigrants). On the other hand Japan has been very averse to immigration.
Why do you think North Africans move to Europe and South Americans move to the US? Because it's the closest country with the best economic opportunities.
Economic immigration is huge. Cultural immigration is tiny.
In fact American culture is the joke of the world (its media can be consumed from wherever and is quite popular, but its values and policies on things like health care, sexual education, religion, crime etc are mocked by more than a few modern economies) and its institutions (e.g. ensuring freedom of speech, freedom of the press, gender equality, life expectancy, racism, gay rights) usually don't find themselves ranked among the top 20, let alone top 10 of countries.
In fact, it's one of the main reasons I wouldn't want to move to the US. I'm in the Netherlands, my partner is American, we could move anytime. But I much prefer the politics, institutions and culture here. (and it's far from perfect here).
I mean you write 'share a wide agreement for rule of law, want to resolve issues through the political process, can usually be shamed into supporting freedom of speech, and don't want to kill their neighbors for having the wrong religion' as if the US is unique in this regard. You write it as if the poorest people on the planet simply want to move to a country that 'doesn't kill its neighbours for having the right religion', as if this is the nr 1 thing on their mind, if only they could move to such a country! That's ridiculous, as opposed to wanting to move to the US for economic opportunities to get a decent standard of life for them and their family.
It's almost entirely money/opportunity. That drives everything.
In Asia, however, the cultural exporters, at the moment, are Japan and Korea, not so much China, despite its economic size. Fortunately and unfortunately, Asia is more pragmatic about cultural imports. There isn't the OMG our indigenous culture is being subverted and devoured!!
The pragmatism is in the form of foreign ideas with Asian values which seems to make the ideas less problematic.
Never the less, I think in many places, it's uncertainty or inferiority and superiority complexes which give rise to ideas of wanting to preserve culture. A fear of change. In the US people lament the change in our culture for 'the worse', as some believe. In other places, similar local changes are interpreted as 'westernization'. But really, do they want to go to how their culture existed in 1900, for example?
South Korea has laws literally banning Japanese TV and music. One South Korean song was banned from broadcast because it had one Japanese word in it.
It has sentimental and historical value, but I don't think it's particularly important. We can argue cultural identity, but that's only important so long as there are various cultures. In a monoculture world, the idea of cultural identity would be a lost concept.
Cultural anthropology, which while highly interesting and informative of human relations, isn't very highly valued by most people. The jobs are in such low demand (and with such low salary) that I decided not to try and get a job as a cultural and linguistic anthropologist. Which, while I'd have loved the work and have found it interesting, I can't exactly say it has much "meaningful" merit.
As for CanCon laws, I've yet to speak to a Canadian that was supportive of them. I'm sure they exist - or the laws wouldn't. A large number of Canadian Netflix users mask their IP to be from America to get "better content" [0]. It seems that Canadian nationalism is mostly a 60's/70's generation thing.
[0] http://o.canada.com/technology/internet/thousands-of-canadia...